TI Designs 32-Bit ARM® Cortex®-M4F MCU-Based Small Form Factor Serial-to-Ethernet Converter TI Designs Design Features TI Designs provide the foundation that you need • TM4C129XNCZAD 32-Bit ARM Cortex-M4F MCU- including methodology, testing, and design files to Based quickly evaluate and customize the system. TI Designs • Integrated 10/100 Ethernet MAC and help you accelerate your time to market. Physical Layer (PHY) Design Resources • 10/100 Ethernet MAC with Advanced IEEE 1588 PTP Hardware and Both Media Independent TIDA-00226 Tool Folder Containing Design Files Interface (MII) and Reduced Media Independent Interface (RMII) Support TM4C129XNCZAD Product Folder TPD4E1U06 Product Folder • Provision to Connect to External Boards for SN75HVD3082E Product Folder Isolated Communication Interface and POE TPS62177 Product Folder • Onboard Nonisolated CAN and RS-485 PHY INA196AIDBVR Product Folder • 50-Pin Connector for External Interface with MII/RMII Ethernet PHY • Expansion Connectors for Access to ASK Our Analog Experts Communication, ADC, and GPIO Interfaces WEBENCH® Calculator Tools • 1024-KB Flash Memory and 256-KB Single-Cycle System SRAM Featured Applications • Industrial Application: Circuit Breakers, Protection Relays, Smart Meters (AMI), and Panel Mount Multi-Function Power and Energy Meters • Substation Automation Products: RTU, Protection Relay, IEDs, Converters, and Gateways • Industrial Remote Monitoring: Remote I/O and Data Loggers 10 Pin Jtag Ethernet PHY Current (Power 5 V ± 3.3 V) 5-LEDs DEBUG TPS62177DQC Amp 3.3 V CAN ± Non Isolated SN65HVD256D RS485 ± Non Isolated SN65HVD3082ED 50 Pin TM4C129XNCZAD SDCC USB ± Non Isolated RJ45 ESD-TPD4E1U06 Eth0 Internal MII/RMII/SPI/I2C/UART interface MAC/ ADC and I/O PHY Spare ± 10 Pin 25M-Crystal Connector Tiva, LaunchPad are trademarks of Texas Instruments. ARM, Cortex, Thumb are registered trademarks of ARM Holdings plc. All other trademarks are the property of their respective owners. TIDU348–June 2014 32-Bit ARM® Cortex®-M4F MCU-Based Small Form Factor Serial-to-Ethernet 1 Submit Documentation Feedback Converter Copyright © 2014, Texas Instruments Incorporated System Description www.ti.com An IMPORTANT NOTICE at the end of this TI reference design addresses authorized use, intellectual property matters and other important disclaimers and information. 1 System Description A simple and effective design makes ethernet the most popular networking solution at the physical and data link levels of the Open Systems Interconnection (OSI) model. With high speed options and a variety of media types to choose from, ethernet is efficient and flexible. In addition, the low cost of hardware makes ethernet an attractive option for industrial networking applications. The opportunity to use open protocols such as TCP/IP over ethernet networks offers a high level of standardization and interoperability. The result has been an ongoing shift to the use of ethernet for industrial control and automation applications. Ethernet is increasingly replacing proprietary communications. 1.1 Serial-to-Ethernet Converter Serial communications (RS-232/422/485) have traditionally been used in industrial automation to connect various instruments such as sensors and data loggers to stand alone monitoring stations such as computers. The limitations of serial communications, such as distance, accessibility, and the amount of data transferred at any one time and speed, has led to a demand for a more flexible means of communicating. When a legacy product contains only a serial port for a configuration or control interface, continuing to access the legacy product through the serial interface can become challenging over time. Newer computers, especially laptops, do not necessarily have serial ports, and a serial connection is limited by cable length (typically 10 m). Using Ethernet in place of the serial port provides many benefits. Although slow to catch up with IT infrastructure in commercial environments, Ethernet is increasingly regarded as the defacto standard of communications in industrial markets. However, the sheer volume of existing serial-based products and the low cost and ease of integrating these ‘legacy’ protocols means that serial communication is strong in many areas of industry. Due to the minimal processing power required, the ruggedness and reliability of connectors, even relatively new products such as GPS receivers continue to adopt RS-232 and RS-485. RS-485 has been the PHY protocol for industrial networks since Modbus was launched by Modicon in the 1970s. Other manufacturers followed Modicon and used protocols such as PROFIBUS DP and INTERBUS. Contemporary systems are Ethernet-based to allow individual "islands of automation" to share data captured throughout the plant and the company, "top floor to shop floor", and in some cases, the world. To enable legacy serial based hardware to take advantage of Ethernet, Serial-to-Ethernet device converters were designed. Ethernet is a more common interface available on computing equipment today: • The legacy product can be shared more easily (instead of changing a cable connection, a new connection over the existing network is made). • 10-m cable length is no longer an issue (subject to tolerance of the increased transmission delay if the two pieces of equipment are separated by several routers or are located on a heavily loaded network segment). 1.2 Gateway Ethernet plays a critical role in automation. One important device in the sub-station of industrial automation is the gateway . The gateway connects legacy devices with RS-485, RS-232, and CAN interface to an Ethernet-enabled network. A gateway can be used to connect the IEDs (without Ethernet connectivity) to supervision systems via Ethernet, TCP-IP, or radio communication. Web-enabled legacy devices in the substation let the designer access information on the electrical installation via a PC with a standard web browser. The gateway functionality simplifies communications architecture and reduces leased line and connection costs. 2 32-Bit ARM® Cortex®-M4F MCU-Based Small Form Factor Serial-to-Ethernet TIDU348–June 2014 Converter Submit Documentation Feedback Copyright © 2014, Texas Instruments Incorporated www.ti.com System Description Figure 1. Diagram of Data Flow in Gateways 1.2.1 Substation Automation Gateway IEC61850 gateways are common applications of Ethernet gateways in substations. This communication gateway maps signals between the protection and control IEDs in industrial or utility substations and higher-level systems such as Network Control Centers (NCC) or Distributed Control Systems (DCS). 1.2.2 Modbus Gateways Modbus gateways support the four most commonly used communication standards, RS-232/485/422 and Ethernet. Modbus is the standard used for communication between a wide range of industrial devices, including PLCs, DCSs, HMIs, instruments, meters, motors, and drives. Although Modbus can be used for both serial devices (RS-232, RS-422, and RS-485) and newer Ethernet devices, the serial and Ethernet protocols are so different that a specialized gateway is required for one protocol to communicate with the other. Modbus gateways support standard Modbus protocols and are capable of converting the Modbus protocols between Modbus RTU/ASCII (Master) to Modbus TCP (Slave). 1.3 Serial Over IP Ethernet Device Server This converter is a bidirectional switching and transmission device from serial port to Ethernet TCP/IP protocol. The converter changes the traditional serial communication to Ethernet communication and realizes speed networking for serial device. The converter uses transparent communicate protocol so that the user does not need to understand complex Ethernet TCP/IP protocol nor modify old serial programs. The low price improves the designer product’s core competition and the easy, flexible configuration and high-availability will satisfy steep demand. 1.4 Advances in Serial-to-Ethernet Technology • Secure data transfer: More traditional Serial-to-Ethernet device servers operated without data encryption, leaving data vulnerable. Secure Socket Layer (SSL) is now used to provide secure end to end data transfer. • Power over Ethernet (PoE): Device servers are now available with support for PoE (802.3af). This reduces cabling and facilitates ease of installation, saving time and money. • Redundant ring operation: Ring redundancy has become common practice in industrial networks, increasing the availability of serial-based devices. Ring redundancy also saves cost in not having to employ an additional Ethernet switch. • Any baud rate: Serial-to-Ethernet device servers now support any data rate up to 1 Mbps, which is useful for specialist devices. • Ethernet I/O modules and remote I/O: These modules integrate digital and analog signals to the Ethernet network to assist Supervisory Control and Data Acquisition (SCADA). Distributed I/O traditionally using RS-485 can now be connected to a Serial to Ethernet device server. These I/O modules can use Simple Network Management Protocol (SNMP) traps, allowing information about the status of digital or analog devices to be easily integrated into existing SNMP deployments (company infrastructure for example). • Using the cellular network: GPRS, 3G, and HSPA are protocols based on IP. The use of software drivers, together with cellular routers with serial connectivity enables virtual COM ports over a cellular network. Mobile applications such as in vehicles and transport, variable message sign, and digital signage are a few examples.